Wireless signaling.



No. 753,863. PATENTED MAR. 8, 1904.

R. A. FESSENDEN. WIRELESS SIGNALING.-

APPLIOATION'IILED SEPT. 28, 1901. I

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PATENTED MAR. 8,1904. R. A. FESSBNDEN. S

. WIRELESS SIGNALING.

APPLIOAT ION FILED SEPT. 28, 1901.

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UNITED STAT-ES Patented March 8, 1904.

PATENT OFFICE] REGINALD A. FESSENDEN, OF MANTEO, NORTH CAROLINA, ASSIGNOR TO THE NATIONAL ELECTRIC SIGNALING COMPANY, OF PITTSBURG, PENN- SYLVANIA, A CORPORATION OF NEWJERSEY.

WIRELESS SIGNALING.

SPECIFICATION forming part of Letters Patent No. 753,863, dated March 8, 1904.

I Application filed September 28, 1901. Serial No. 76,837. (No model.)

To all whom it may concern.-

Be it known that I, REGINALD A. FESSEN- DEN, a citizen of the United States, residing at Manteo, in the county of Dare and State of North Carolina, have invented or discovered certain new and useful Improvements in Wireless Signaling, of which improvements the following is a specification.

The invention described herein relates to certain improvements in the Wireless transmission of signals, said improvements relating more especially to the transmission and reproduction of Words or other audible signals. In general terms the invention consists in '15 the generation and reception of electromagnetic waves or impulses of a predetermined character and the modification of the character of the waves by sound-waves or other de-,

sired means.

By the term electromagnetic waves as used herein is meant Wa es of a wave length longin comparison with the Wave length of what are commonly called heat-waves or radiant heat. By grounded conductor 2 5 is meant a conductor grounded either directly or through a capacity, an inductance, or a resistance, so that the current in the conductor flows from the conductor to ground, and vice versa, when the electromagnetic waves are 0 generated.

The invention is hereinafter more fully described and claimed.

In theaccompanying drawings, forming a part of this specification, Figure 1 is 2. dia- 3 5 grammatic View illustrating forms of apparatus for the sending and receiving stations. Fig. 2 is a similar view illustrating a modification of the sending apparatus, and Fig. 3 illustrates a further modification of the sending apparatus. 1

In the practice of my invention I provide at the sending-station a conductor 1 of suitable construction and arrangement and connect the same to one terminal of a coil 2, surrounding a core3, preferably annular in shape and preferably formed of-fine iron wire. The other terminal of the coil is connected to one of the knobs or terminals 4 of an induction-coil or other suitable generator 6 capable of producing practically continuous and rapid oscillations in the conductor. The systems described in connection with Fig. 10 of Patent N o. 7 06,7 42 or in PatentN 0. 730,7 53 are well adapted for this purpose. The other terminal, 5, of the generator is connected to ground. A second coil 7 forming a part of the circuit for the battery 8, is-placed on the core 3, and a transmitter 9, preferably microphonic in construction, or other mechanism capable of modifying the current in the circuit is included in the circuit of the battery and coil 7. A capacity l8 and inductance 19 are connected in shunt to the sparkgap for the purpose of I maintaining sustained oscillations of practically constant frequency. The capacity 18 and inductance 19 should be arranged to have the same period of oscillation as the receivingconductor 10 and the sending-conductor 1. It will be seen that the circuit containing capacity 18 and inductance 19, being connected across the spark-gap, forms a parallel circuit in the sending-conductor 1, Whose aerial and grounded sections are also connected across the spark-gap. On account of the fact that the circuit 18 19 and the sending-conductor 1 are in parallel and not in series the diiference of potential across these two circuits is the same, While the currents in the two circuits are different, this construction being thus differentiated from a series connection, in which the circuit 18 19 would be connected electrically between the aerial portion of the plate or coil of wire secured thereto,or any other suitable construction adapted .to yibrate in unison with changes of current or voltages produced by the aves radiated from the send-- ing-station is suitably supported in operative relation to the coil 11. The apparatus at the receiving-station is tuned or made resonant by any suitable means known in the art to the sending-conductor 1. The terms tuned and resonant are used herein one to include the other. When an alternating current is set up in the conductor 10, as by waves or impulses from the sending-station, such current acts to repel or attract the diaphragm, according to the time constant of the metal part of the diaphragm, through induced currents set up in the diaphragm. hen the generator is operated, the diaphragm 12 will take up a mean position relative to coil 11, the distance of such position from the coil varying with the intensity of the oscillations in the sending-conductor; but when the current in the circuit of the coil 7 is modified or changed by speaking into the transmitter the permeability of the core 3 is correspondingly changed or modified, thereby producing a corresponding change or modification in the self inductance and a change in the frequency of the natural period of vibration of the sending-conductor 1,which is thereby thrown out of resonance with a resonating-circuit 18 19, connected in parallel to said sending-conductor 1, and due to this failure in resonance producing a corresponding change or modification in the intensity of the waves or impulses given off by the conductor 1 and in the intensity of the oscillations produced in the receiving-conductor. The changes in the intensity of the oscillations will produce corresponding changes in the mean position of the diaphragm, such changes corresponding to the vibrations of the diaphragm of the transmitter, exactly reproducing any of the waves or impulses which affected the transmitter. The same result may be effected by changing the capacity of the conductor 1, as shown in Fig. 2. To this end the conductor 1 is connected to a fixed plate 13 of a condenser, while the other plate, 14, is formed by or connected to a diaphragm capable of responding to waves or impulses. As the plate 14 in vibrating moves toward or from the other plate the capacity of the conductor 1 is changed, correspondingly altering the intensity of the waves or impulses generated by the conductor.

Instead of using an induction-coil and sparkgap an alternating-current generator of high periodicity-as, for example, of fifty thousand per second-may be used, as shown in Fig. 3. It is preferred that the generator should be of the character described in application, Serial No. 62,301, filed March 29, 1901. One terminal of the generator 15 is connected to the sending-conductor and the other terminal to ground. A microphonic contact 16 may be interposed, as shown, in the circuit of the sending generator and conductor, the microphonic contact forming part of a carbon transmitter, the diaphragm of which is indicated at 17. The microphonic contact should be of the kind used in what are known as speaking arc-lights and capable of working with currents of ten to one hundred amperes or more if the waves generated are very intense. Its operation is as follows: The sending-conductor has its natural period in resonance with the period of the dynamo, and the amount of the resonant voltage depends upon the resistance of the microphonic contact. Hence speaking against the diaphragm the amount of the voltage is changed to correspond with the sound-waves. This microphonic contact may also be used in place of the variable inductance shown in Fig. 1 or the variable capacity shown in Fig. 2 in connection with the induction-coil and the auxiliary circuit 18 19.

It is characteristic of my improvement that waves or impulses are generated at the sending-station and received at the other station and that the signaling is affected not by interruption of the flow of waves or impulses, but by a modification or change in the character of the waves or impulses. Many ways of modifying or changing the waves will readily suggest themselves to those skilled in the art, and hence as regards the broader features of my invention I do not limit myself to any particular method or mechanism for modifying the waves or impulses.

The term signaling is used herein in a broad sense, and especially as including the transmission and receipt of words, sounds, characters, 620.

I claim herein as my invention- 1. As an improvement in the art of signaling by electromagnetic waves the method herein described which consists in the practically continuous transmission and reception of electromagnetic waves or impulses, and modifying or changing the character of such Waves or impulses without interruption of their continuity, substantially as set forth. 1

2. As an improvement in the art of signaling by electromagnetic waves the method herein described which consists in the practically continuous transmission and reception of electromagnetic waves or impulses, and continuously modifying or changing the character of such waves or impulses without interruption of their continuity, substantially as set forth.

8. As an improvement in the art of signaling by electromagnetic waves the method herein described, which consists in the transmission and reception of electromagnetic waves or impulses and modifying or varying the character of a portion of such waves or impulses without interruption of their continuity, substantially as set forth.

4. As an improvement in the art of signaling by electromagnetic Waves the method herein described, which consists in the transmission and reception of electromagnetic waves orimpulses of uniform character and continuously modifying or varying the character of a por- IIO tion of such Waves or impulses without interruption of their continuity, substantially as set forth.

5. As an improvement in the art of transmitting sounds by electromagnetic waves the method herein described, which consists in the generation of electromagnetic waves or impulses and modifying or varying the character of such waves or impulsesby sound waves or impulses without interruption of their continuity, substantially as set forth.

6. As an improvement in the art of signaling by electromagnetic waves, the method herein described which consists in the practically continuous transmission and reception of electromagnetic waves or impulses normally of a predetermined character and modifying or changing the character of such waves or impulses without interrupting their continuity by changing the electrical constants of the sending-conductor so as to change the degree of resonance between the generator and sending-conductor, substantially as set forth.

7 As an improvement in the art of signaling by electromagneticwaves the method herein described which consists in the practically continuous generation of waves or impulses and modifying or changing the intensity of said Waves Without interrupting their conti nuity, thereby rendering them capable of affecting a receiving-conductor, tuned to correspond with sending-conductor, during only a portion of. the time. i

8. As an improvement in the art of signaling by electromagnetic waves the method herein described which consists in the practically continuous generation of waves or impulses and modifying or changing the intensity of such waves or impulses Without interrupting their continuity by changing the resistance in the sending-conductor.

v9. As an improvement in the art of signaling by electromagnetic Waves the method herein described which consists in the practically continuous. generation of Waves or impulses and modifying or changing the intensity of said waves without interrupting their'continuity, thereby rendering them capable of affecting a receiving-conductor tuned to correspond with the sending-conductor, to different degrees at different times.

10. As an improvementin the art of signaling by electromagnetic waves the method herein described, which consists in the practically continuous transmission and reception of elecin described, which consists in the practically continuous transmission and reception of electromagnetic waves or impulses normally of a predetermined character and continuously modifying or changing the character of such waves or impulses without interruption of their continuity, substantially as set forth.

12. As an improvement in the art of transmitting sounds by electromagnetic waves the method herein described, which consists in the generation of electromagnetic Waves or impulses normally of uniform character, and modifying or varying the character of such waves or impulses by sound waves or impulses without interruption of their continuity, substantially as set forth.

18. As an improvement in the art of signaling by electromagnetic waves the method herein described, which consists in the practically continuous transmission and receipt of electromagnetic waves, and modifying the character of said waves at the sending-station without. interrupting their continuity, substantially as set forth.

1&. As an improvement in the art of signaling by electromagnetic waves the method herein described, which consists in the practically continuous generation of electromagnetic waves or impulses of constant periodicity, and modifying or changing the intensity of such Waves or impulses without interrupting their continuity, substantially as set forth.

15. As an improvement in the art of signaling by electromagnetic Waves the method herein described, which consists in the practically continuous generation of electromagnetic.

waves or impulses of constant periodicity, and modifying or changing the intensity of such waves or impulses by changing the resistance of the sending-conductor without interrupting the continuity of the waves, substantially as set forth.

In testimony whereof I have herereunto set my hand.

REGINALD A.-FESSENDEN. Witnesses;

DARWIN S. WOLCOTT, THEO. S. 'MUKINs. 

